Current radio access systems are generally divided into two types, and one type is based on a centralized control technique, for example, a long term evolution (LTE) technique and an IEEE 802.16 technique. According to such technique, a certain host in a network is taken as a command center for managing the whole network, and other hosts have to first obtain permission from the commander before transmitting data. Another type is based on a distributed control technique, for example, an IEEE 802.11 technique. According to such technique, one host in the network has to contend for access right before executing data transmission, and the other hosts have to wait for a next chance to contend for transmitting data.
FIG. 1 is a data transmission schematic diagram of the above two radio access systems. In the radio access system of the IEEE 802.11 technique, when a transmission medium is applicable, different mobile devices are in contention for an applicable resource to transmit data. The mobile device acquiring the resource may directly transit a single block with a different data length. In the radio access systems of the LTE and IEEE 802.16 technique, a data transmission process could be divided into two phases. In a first stage, the mobile device first transmits preambles to contend a resource grant before transmitting data packets. If the contention is successful, a base station transmits the resource grant to indicate the resource allocated to the mobile device, so as to facilitate transmitting the data packets in a second stage. In other words, the mobile device first confirms that the resource is applicable before transmitting the data packets. Therefore, the mobile device of the LTE and IEEE 802.16 technique may have to spend time to acquire the permission of the resource grant.
In specifications of 3GPP LTE TS 22.368, regarding small or sliced data transmission, a plurality of solutions are prepared to avoid overhead and signal latency. A current consensus is that the system should support transmission of the small amount of data under a minimal network impact. These solutions are also prepared to avoid signalling overhead caused by random access, additional latency caused by scheduling request (SR) of the mobile devices and overprotect of a static resource used for small or sliced data transmission.
Moreover, a transmission capacity of physical downlink control channels (PDCCHs) in the LTE system still has some situations required to be avoided. Taking a system bandwidth of 10 MHz as an example, about 10 PDCCHs are transmitted within one basic transmission time interval (TTI). The PDCCHs are used to schedule dedicated user equipments (UEs) for transmitting data. Since a part of control channel elements (CCE) of the PDCCH is used for certain purposes, for example, system information, random access and transmission power control, etc., in an example of reserving 3 or 2 orthogonal frequency division multiplexing (OFDM) symbols for PDCCH transmission in one basic TTI, regarding the dedicated scheduling, one PDCCH only has about 25 or 10 applicable CCEs. However, one subframe may have 50 resource blocks (RB), and if most of downlink assignments are small assignments, i.e. one resource block corresponds to one physical downlink shared channel (PDSCH), the number of the CCEs probably cannot indicates all of the resource blocks. In this way, a situation in control channel transmission capacity is occurred, which means that the number of the control channels is inadequate to indicate all of the data transmissions. If the indication for transmitting multiple RBs can be shared, such situation is avoided.